Rollup merge of #124183 - compiler-errors:unnecessary-by-ref, r=oli-obk

Stop taking `ParamTy`/`ParamConst`/`EarlyParamRegion`/`AliasTy` by ref

It's unnecessary and is annoying when we have it by value.

2 files changed, 6 insertions, 6 deletions

diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
index db3794c1c40..9d3caaa01ab 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -124,7 +124,7 @@ pub fn suggest_restriction<'tcx, G: EmissionGuarantee>(
     msg: &str,
     err: &mut Diag<'_, G>,
     fn_sig: Option<&hir::FnSig<'_>>,
-    projection: Option<&ty::AliasTy<'_>>,
+    projection: Option<ty::AliasTy<'_>>,
     trait_pred: ty::PolyTraitPredicate<'tcx>,
     // When we are dealing with a trait, `super_traits` will be `Some`:
     // Given `trait T: A + B + C {}`
@@ -142,7 +142,7 @@ pub fn suggest_restriction<'tcx, G: EmissionGuarantee>(
     let generics = tcx.generics_of(item_id);
     // Given `fn foo(t: impl Trait)` where `Trait` requires assoc type `A`...
     if let Some((param, bound_str, fn_sig)) =
-        fn_sig.zip(projection).and_then(|(sig, p)| match p.self_ty().kind() {
+        fn_sig.zip(projection).and_then(|(sig, p)| match *p.self_ty().kind() {
             // Shenanigans to get the `Trait` from the `impl Trait`.
             ty::Param(param) => {
                 let param_def = generics.type_param(param, tcx);
@@ -252,7 +252,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         let trait_pred = self.resolve_numeric_literals_with_default(trait_pred);
 
         let self_ty = trait_pred.skip_binder().self_ty();
-        let (param_ty, projection) = match self_ty.kind() {
+        let (param_ty, projection) = match *self_ty.kind() {
             ty::Param(_) => (true, None),
             ty::Alias(ty::Projection, projection) => (false, Some(projection)),
             _ => (false, None),
diff --git a/compiler/rustc_trait_selection/src/traits/mod.rs b/compiler/rustc_trait_selection/src/traits/mod.rs
index 8f5a30c436d..88ebf8754d3 100644
--- a/compiler/rustc_trait_selection/src/traits/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/mod.rs
@@ -482,7 +482,7 @@ fn is_impossible_associated_item(
         type Result = ControlFlow<()>;
         fn visit_ty(&mut self, t: Ty<'tcx>) -> Self::Result {
             // If this is a parameter from the trait item's own generics, then bail
-            if let ty::Param(param) = t.kind()
+            if let ty::Param(param) = *t.kind()
                 && let param_def_id = self.generics.type_param(param, self.tcx).def_id
                 && self.tcx.parent(param_def_id) == self.trait_item_def_id
             {
@@ -492,7 +492,7 @@ fn is_impossible_associated_item(
         }
         fn visit_region(&mut self, r: ty::Region<'tcx>) -> Self::Result {
             if let ty::ReEarlyParam(param) = r.kind()
-                && let param_def_id = self.generics.region_param(&param, self.tcx).def_id
+                && let param_def_id = self.generics.region_param(param, self.tcx).def_id
                 && self.tcx.parent(param_def_id) == self.trait_item_def_id
             {
                 return ControlFlow::Break(());
@@ -501,7 +501,7 @@ fn is_impossible_associated_item(
         }
         fn visit_const(&mut self, ct: ty::Const<'tcx>) -> Self::Result {
             if let ty::ConstKind::Param(param) = ct.kind()
-                && let param_def_id = self.generics.const_param(&param, self.tcx).def_id
+                && let param_def_id = self.generics.const_param(param, self.tcx).def_id
                 && self.tcx.parent(param_def_id) == self.trait_item_def_id
             {
                 return ControlFlow::Break(());